I've only owned my Vita for like 3 months now and I own 18 games.
Retail:
Persona 4 Golden
NFS Most Wanted
Soul Sacrifice
Uncharted: Golden Abyss
AC III Liberation
FIFA 13
Sly Cooper: Thieves in Time
Reality Fighters
Tearaway
Download:
Playstation All-Stars
Sound Shapes
Retro City Rampage
Hotline Miami
Super Stardust Delta
CastleStorm
Rayman Origins
Rainbow Moon
Escape Plan